Research trends in functionalized and doped graphene catalysts for proton-exchange membrane fuel cells: A bibliometric analysis

Catalysts are a crucial component of fuel cells, and graphene-based catalysts have been extensively studied as cost-effective alternatives to Pt catalysts. This study aims to investigate the issues of functionalized and doped graphene as a catalyst for proton-exchange membrane fuel cells (PEMFCs) and analyze the trends through bibliometric analysis. Data were retrieved from the Scopus database, including 1175 scientific articles published between 2008 and 2023 and excluding review papers. VOSviewer and Publish or Perish software were used to analyze the data and obtain information regarding publication and citation metrics, author countries, most cited papers, subject areas, co-authorship, and keyword co-occurrence for mapping research trends. The results revealed fluctuations in the annual publication and citation metrics of articles on functionalized and doped graphene-based catalysts during the research period. Wang et al. published the highest number of articles. The authors demonstrated global cooperation on many interrelated research topics. The 2011 study by Liang et al. on catalyzing CO 3 O 4 nanocrystals in graphene was the most cited. Finally, keyword co-occurrence analysis identified research trends in PEMFA development, such as 1) developing carbon sources for PEMFC catalysts and 2) optimizing Pt group metal-free PEMFC catalysts. Thus, this study provides an overview of research hotspots on functionalized and doped graphene-based catalysts for PEMFCs and highlights their potential to drive innovation. Future work should address the stability and cost-effectiveness of functionalized and doped graphene compared to commercial Pt/C catalysts in improving PEMFV performance.